1. Technical Field
This invention relates to vehicles in general, and to vehicular suspensions capable of controlling vehicle roll and pitch, in particular.
2. Background Information
The suspension of a vehicle determines the ride characteristics of the vehicle such as its roll and pitch. The term xe2x80x9crollxe2x80x9d refers to rotational movement of the vehicle body about a longitudinal axis of the vehicle. Roll is typically encountered during cornering. The term xe2x80x9cpitchxe2x80x9d refers to rotational movement of the vehicle body about a widthwise axis of the vehicle. Pitch is typically encountered during acceleration (acceleration xe2x80x9csquatxe2x80x9d) and during braking (braking xe2x80x9cdivexe2x80x9d).
Vehicle suspension systems can be characterized as either active or passive. xe2x80x9cActivexe2x80x9d suspension systems typically adjust suspension elements during use in response to sensed operating conditions. Active suspension systems are often relatively complex, prohibitively expensive, or both. Passive suspension systems, on the other hand, typically include anti-roll or stabilizer bars, or the like that cannot be adjusted during use. Passive suspension systems are typically relatively simple and affordable.
In passive suspension systems that utilize elements such as springs and anti-roll bars to reduce cornering roll, there is a trade-off between reduction in roll and the smoothness of the ride. Spring and shock rates that increase the smoothness of the ride often counteract the effect of conventional anti-roll devices. Moreover, such anti-roll devices do not compensate for variations in weight distribution of the vehicle that can also significantly affect rolling characteristics.
What is needed, therefore, is a vehicular suspension system that provides favorable roll and pitch characteristics.
It is, therefore, an object to provide a vehicular suspension system that provides favorable roll and pitch characteristics.
According to the present invention, a suspension for a vehicle having a body is provided. The suspension includes a first wheel assembly suspension and a second wheel assembly suspension. The first wheel assembly suspension extends between a first wheel assembly and the body. The first wheel assembly suspension includes an instant center. The second wheel assembly suspension extends between a second wheel assembly and the body. The second wheel assembly suspension includes an instant center. The first wheel assembly and the second wheel assembly are aligned so that a vertical centerline of each wheel assembly lies within a vertical plane that extends therebetween. In one embodiment, the instant center of each wheel assembly suspension is located within the vertical plane, below a roll center located within the vertical plane.
According to a further aspect of the invention, a method for suspending a vehicle having a body is provided that includes the steps of: (1) providing a first wheel assembly suspension that extends between a first wheel assembly and the body, wherein the first wheel assembly suspension includes an instant center; (2) providing a second wheel assembly suspension that extends between a second wheel assembly and the body, wherein the second wheel assembly suspension includes an instant center; (3) aligning the first wheel assembly and the second wheel assembly so that a vertical centerline of each wheel assembly lies within a vertical plane that extends therebetween; and (4) positioning the first wheel assembly suspension and the second wheel assembly suspension so that the instant center of each wheel assembly suspension is located within the vertical plane, below a roll center located within the vertical plane.
An advantage of the present suspension is that it is possible to create a relatively high and stable roll center using the present suspension, and therefore a desirable stable vehicular suspension. The relatively high roll center can be maintained in approximately the same position during expected motion of the vehicle.
These and other objects, features, and advantages of the present invention will become apparent in light of the drawings and detailed description of the present invention provided below.